Echo: BodyDump captures request and response bodies without size limits in v4

Echo is a Go web framework. From 4.0.0 until 4.16.1, Echo v4's opt-in BodyDump middleware reads complete request bodies into memory before handlers run and retains complete response bodies for the dump callback without capture limits. An unauthenticated client that can reach a route using BodyDump can submit large bodies or influence large responses, causing repeated or concurrent allocations that exhaust process memory. BodyDump is not enabled by default, and external request limits may reduce request-side exposure but do not bound response capture. This issue is fixed in 4.16.1.